1. Field of the Invention
The present invention relates to connectors having a conductive shell and a center contact, and in particular, to connectors that are mounted on a circuit board.
2. Description of Related Art
Some connectors are designed to mount on circuit boards. These connectors are often soldered in place on the board. In many cases the connector will have a metal shell with a coaxial metal contact. The distal end of the connector may also have a male (female) fitting that is externally (internally) threaded to accept a mating threaded connector at the end of a cable. Instead of threads, other connectors may have a bayonet fitting, friction fitting, etc.
Connectors must deal with advancing technology that has allowed electronic equipment to handle much higher frequencies. Great advances have been achieved in digital electronics with ever faster clock rates and pulse rise times. With the advent of high-definition television, higher frequency demands have become routine.
In such a high-frequency environment, transferring signals between a cable and a circuit board is more demanding. To transfer electromagnetic energy efficiently, discontinuities ought to be avoided at the connection between the cable and circuit board. For example, cables such as coaxial cables have a characteristic impedance and should be terminated into a matching impedance to avoid reflections. Also, the geometry of the transition should be a designed carefully to avoid irregularities that can cause reflections as well. In addition, one must take into account the dielectric coefficient of intervening elements, including the dielectric coefficient of relevant volumes of air.
The geometry of the connector can determine whether there are discontinuities or other mismatching effects. This geometry is especially important since high-frequency connectors often include metal components and these metal bodies can have capacitive and inductive effects. The undesired presence of such capacitance and inductance may produce a mismatch that can adversely affect the transfer efficiency of the connector.
While high-frequency connectors ought to work well under these demanding conditions, their structure should also be simple, rugged and dependable. Further-more, and assembler should be able to easily and reliably install the connector on a circuit board.
See also U.S. Pat. Nos. 5,404,117; 5,823,790; 5,897,384; 6,106,304; 6,254,399; 6,407,652; 6,457,979; 6,682,354; 6,791,317; 6,811,405; 6,957,980; 7,042,318; 7,048,547; and 7,344,381, as well as U.S. Patent Application Publication Nos. 2004/0038587; 2008/0045043; and 2008/0102654.